chromeos: call GetIdleTime from power manager client

chrome/browser/chromeos/dbus/power_manager_client.h

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CHROME_BROWSER_CHROMEOS_DBUS_POWER_MANAGER_CLIENT_H_
 #define CHROME_BROWSER_CHROMEOS_DBUS_POWER_MANAGER_CLIENT_H_
 
+#include "base/callback.h"
 #include "base/memory/ref_counted.h"
 #include "base/observer_list.h"
 
 #include <string>
 
 namespace dbus {
 class Bus;
 class ObjectProxy;
 class Response;
 class Signal;
@@ skipping 11 matching lines @@
   // Time in seconds until the battery is empty or full, 0 for unknown.
   int64 battery_seconds_to_empty;
   int64 battery_seconds_to_full;
 
   double battery_percentage;
 
   PowerSupplyStatus();
   const std::string& ToString() const;
 };
 
+typedef base::Callback<void(int64_t)> CalculateIdleTimeCallback;

[satorux1, 2011/11/15 00:57:42]

Please add some comment about the parameter: int64_t.

[Simon Que, 2011/11/15 01:29:38]

Done.

+
 // PowerManagerClient is used to communicate with the power manager.
 class PowerManagerClient {
  public:
   // Interface for observing changes from the power manager.
   class Observer {
    public:
     // Called when the brightness is changed.
     // |level| is of the range [0, 100].
     // |user_initiated| is true if the action is initiated by the user.
     virtual void BrightnessChanged(int level, bool user_initiated) {}
@@ skipping 16 matching lines @@
 
   // UI initiated request for power supply status update.
   virtual void RequestStatusUpdate() = 0;
 
   // Requests restart of the system.
   virtual void RequestRestart() = 0;
 
   // Requests shutdown of the system.
   virtual void RequestShutdown() = 0;
 
+  // Calculates idle time asynchronously. If it encounters some error,
+  // it returns -1.

[satorux1, 2011/11/15 00:57:42]

The comment is misleading. It's a void function. You can say something like

If it encounters some error, -1 is passed to |callback|.

BTW, on success, what value is passed? Please also document.

[Simon Que, 2011/11/15 01:29:38]

Done.

+  virtual void CalculateIdleTime(CalculateIdleTimeCallback* callback) = 0;

[satorux1, 2011/11/15 00:57:42]

This shouldn't have to be a pointer. Please remove *, and fix the caller.

[Simon Que, 2011/11/15 01:29:38]

Done.

+
   // Creates the instance.
   static PowerManagerClient* Create(dbus::Bus* bus);
 
   virtual ~PowerManagerClient();
 
  protected:
   // Create() should be used instead.
   PowerManagerClient();
 
  private:
   DISALLOW_COPY_AND_ASSIGN(PowerManagerClient);
 };
 
 }  // namespace chromeos
 
 #endif  // CHROME_BROWSER_CHROMEOS_DBUS_POWER_MANAGER_CLIENT_H_